.TH std::experimental::filesystem::file_size 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::experimental::filesystem::file_size \- std::experimental::filesystem::file_size

.SH Synopsis
   Defined in header <experimental/filesystem>
   std::uintmax_t file_size( const path& p );                 \fB(1)\fP (filesystem TS)
   std::uintmax_t file_size( const path& p, error_code& ec );

   Returns the size of the regular file p, determined as if by reading the st_size
   member of the structure obtained by POSIX stat (symlinks are followed).

   Attempting to determine the size of a directory (as well as any other file that is
   not a regular file or a symlink) is treated as an error.

   The non-throwing overload returns returns -1 on errors.

.SH Parameters

   p  - path to examine
   ec - out-parameter for error reporting in the non-throwing overload

.SH Return value

   The size of the file, in bytes.

.SH Exceptions

   The overload that does not take an error_code& parameter throws filesystem_error on
   underlying OS API errors, constructed with p as the first argument and the OS error
   code as the error code argument. std::bad_alloc may be thrown if memory allocation
   fails. The overload taking an error_code& parameter sets it to the OS API error code
   if an OS API call fails, and executes ec.clear() if no errors occur. This overload
   has
   noexcept specification:
   noexcept


.SH Example


// Run this code

 #include <experimental/filesystem>
 #include <fstream>
 #include <iostream>
 namespace fs = std::experimental::filesystem;

 int main()
 {
     fs::path p = fs::current_path() / "example.bin";
     std::ofstream(p).put('a'); // create file of size 1
     std::cout << "File size = " << fs::file_size(p) << '\\n';
     fs::remove(p);

     try
     {
         fs::file_size("/dev"); // attempt to get size of a directory
     }
     catch (fs::filesystem_error& e)
     {
         std::cout << e.what() << '\\n';
     }
 }

.SH Possible output:

 File size = 1
 filesystem error: cannot get file size: Is a directory [/dev]

.SH See also

   resize_file changes the size of a regular file by truncation or zero-fill
               \fI(function)\fP
   space       determines available free space on the file system
               \fI(function)\fP

.SH Categories:
     * Noindexed pages
     * unconditionally noexcept
.SH Hidden categories:
     * Pages with unreviewed unconditional noexcept template
     * Pages with unreviewed noexcept template
